In light of its favorable energy content, natural gas may be used as a fuel source for an engine. To obtain fuel economy benefits and meet power output demands over a wide range of operating conditions, some engines may be configured to operate with both natural gas and a liquid fuel, such as diesel. In such multi-fuel engines, the natural gas/intake air mixture in each cylinder of the engine may be combusted in response to an injection of liquid fuel. While some operating conditions may benefit from a relatively high ratio of natural gas to liquid fuel (e.g., 90% natural gas or greater), the amount of natural gas used in a given engine cycle may be limited by the lowest-possible amount of liquid fuel each fuel injector is capable of injecting.